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| − | {{Definition|title=Geographical Information system (GIS)
| + | #Redirect[[Geographical Information System (GIS)]] |
| − | |definition=Geographical Information System (GIS) is a tool for analysis and presentation of spatial data. It is a collection of computer hardware, software and geographic data for capturing, managing, analysing and displaying all forms of geographically referenced information.
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| − | ==What is GIS?==
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| − | [[Image:GISdefinition.jpg|thumb]] | |
| − | A Geographic Information System organizes large volumes of raw data into a map form for easy comprehension. It divides raw data into layers so it can give you a better understanding for the whole world.
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| − | A GIS is designed for the collection, storage, and analysis of objects and phenomena where geographic location is an important characteristic or critical to the analysis - this definition is broad and applies to a wide variety of methods for storing, accessing, and manipulating geographic information; it does not limit GIS to the computer environment<ref name="Cox">Cox, A., Gifford, F. An overview to geographic information systems. The Journal of Academic Librarianship, Volume 23, Issue 6, November 1997, Pages 449-461</ref> .
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| − | ===Why is GIS unique?===
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| − | GIS handles SPATIAL information - i.e. information referenced by its location in space
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| − | [[Image:Spatialinfo.jpg|400px|centre]]
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| − | ==GIS Data==
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| − | GIS stores ''geographic coordinate data'' (spatial data) and ''attribute data''.
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| − | '''Spatial data:'''
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| − | *represent features having known locations on earth
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| − | *one of: points (0D), lines (1D) or areas (2D)
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| − | '''Attribute data:'''
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| − | *non-graphic information linked to the geographical features (spatial data) describing features eg type of road, name, history.
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| − | ===Data formats===
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| − | Two basic formats for storing and processing coordinate data: Vector and Raster
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| − | '''Vector:'''
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| − | *uses point locations (X,Y coordinate)
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| − | *advantage: less storage space
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| − | *disadvantage: may be more difficult to perform certain overlay functions
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| − | '''Raster:'''
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| − | *data stored as a matrix of pixels, representing points.
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| − | *to analyse or overlay multiple data layers, the layers must share a common projection and coordinate system, and layers must have topology established
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| − | *Disadvantage: it is necessary to store the entire matrix
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| − | *Advantage: can perform neighbourhood analysis easily
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| − | ===Data types===
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| − | [[Image:Mike21data.jpg|thumb|right|Dfs1 Data MIKE 21]]
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| − | *DFS2 Data MIKE 21
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| − | *Dfs1 Data MIKE 21
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| − | *XYZ Data
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| − | *Wave time series & Rose
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| − | *Scanned Maps
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| − | *CAD drawing
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| − | [[Image:CADdrawing.jpg|thumb|right|CAD drawing]]
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| − | '''Additional Data'''
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| − | *Land use
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| − | *Sediment classification
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| − | *Satellite images
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| − | *Geographical maps
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| − | *Reports (design, licenses, Site investigation), etc.
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| − | Map data is separated and stored in layers usually based on common geographical themes or data type. And alternative is objected-oriented GIS, where geographical and all other information regarding a feature stored as an object.
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| − | ==GIS functions==
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| − | *Data input
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| − | *Storage
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| − | *Management
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| − | *Analysis
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| − | *Output
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| − | ===Data input===
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| − | Data input can by via:
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| − | *keyboard entry
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| − | *digitising maps
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| − | *digital scanning (like a photocopy)
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| − | ===Storing data using Geodatabase===
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| − | Geodatabase is a container for spatial and non- spatial data that can be organized in a certain structure. It has the following advantages:
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| − | *GIS provides a single, consolidated data storage for field measurements and all types of data used.
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| − | *the ability of controlling data entry by applying validation rule on the attributes.
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| − | [[Image:Geodatabase.jpg|400px|centre]]
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| − | ===Data management===
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| − | Database management system controls the way data are stored and retrieved. This includes verifying geographic coordinates and examining for accuracy.
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| − | ===GIS analysis===
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| − | GIS analysis creates new data by manipulating existing data or analyzing relationships between sets of data. It's basic operations include:
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| − | *retrieval
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| − | *map generalization
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| − | *map abstractions
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| − | *map sheet manipulation
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| − | *map abstractions
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| − | *map sheet manipulation
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| − | *buffer generation
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| − | *polgygon overlay and dissolve
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| − | *measurements
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| − | *digital terrain analysis, and
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| − | *network analysis<ref name="Cox"/>
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| − | ===Output===
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| − | The display of output is achieved through printers and computer screens.
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| − | ==Benefits of GIS==
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| − | GIS has many benefits, which include:
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| − | *ability to integrate different databases into one environment
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| − | *ability to display and manage spatial data in a spatial contect
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| − | *rapid production of specialized map and graphic products
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| − | *performs complex spatial analysis
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| − | ==CZM and GIS==
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| − | *GIS stores all data relevant for the [[CZM]]
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| − | *GIS handles data on all spatial scales (North Egypt coast vs. a single harbour)
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| − | *GIS is a powerful analysis tool, allowing the comparison of measurements from different years, as well as overlay analysis of measurements and modelling results.
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| − | [[Image:GISCZM3.jpg|400px|centre|Coastal Zone management: GIS perspective]]
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| − | ==External links==
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| − | *[http://www.gisig.it/ GISIG] –- - Geographical Information Systems International Group
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| − | *[http://www.geo.ed.ac.uk/home/giswww.html GIS WWWW resource list] of servers likely to be of interest to the GIS community
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| − | *[http://support.esri.com/index.cfm?fa=knowledgebase.gisDictionary.gateway GIS dictionary]
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| − | *[http://en.wikipedia.org/wiki/Geographic_information_system Wikipedia: GIS]
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| − | ==References==
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| − | <references/>
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| − | ''8th January, Ulrik Lumborg, DHI.''
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| − | (Caitlin 09:53, 18 January 2007 (Romance Standard Time))
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